1. Field of the Disclosure
The present disclosure relates to an orthopedic implant. More particularly, the present disclosure relates to an orthopedic implant that may be used to repair and/or replace focal defects in an individual's articular cartilage.
2. Description of the Related Art
Due to a variety of factors, an individual may develop defects in the articular cartilage of a bone. For example, an individual may develop a focal defect in the articular cartilage of the femur and/or tibia in the knee joint. FIG. 1 depicts an illustration of a femur tibia joint 1 which includes a femur 2 and tibia 3. Condyle 4 of femur 2 has a tissue defect 5. More particularly, defect 5 is a defect of the articular cartilage. In some instances, defect 5 may extend through the articular cartilage and into the bone of femur 2.
Such defects may be rather small in size, but can cause the individual to experience substantial pain during joint articulation. Additionally, these defects may develop on opposing sides of the joint (i.e., in the articular cartilage of both femur 2 and tibia 3) and, during articulation of the joint, the defects may come into contact with one another, i.e., may form “kissing legions”. In situations where the walls of opposing kissing legions come in contact, they may frictionally engage one other in a manner that exerts sufficient forces on the legions to cause further damage to the articular cartilage and, correspondingly, cause the legions to increase in size. As a result, with successive articulation of the joint, the legions may continue to expand and extend into the bone.
Current treatment options for repairing focal defects, such as kissing legions, can be effective. For example, mosaicplasty may be performed, which uses a bone plug to replace the cartilage in the area of the focal defect. FIG. 2 shows a cross-sectional view of a femur tibial joint in which bone plugs 6 have been implanted into femur 4. Femur 2 has inner cancellous bone 7 and covered by outer dense contact bone 8. The compact bone of the femur in the condyle region is covered by a layer of articular cartilage 9. Tibia 3 includes similar bone and cartilage structure. In order to insert bone plugs 6, a hole for the receipt of bone plug 6 must be formed through the articular cartilage layer 9 and into the individual's compact bone 8 and cancellous bone 7, resulting in a loss of some of the individual's natural bone stock. Additionally, if the bone plug 6 is taken from the individual, i.e., is an autograft, an additional incision may need to be made and the patient will also experience increased healing time and additional pain. Bone plugs 6 typically include the same tissue and structure of the area being repaired. That is, bone plugs 6 include a cancellous bone portion 11, a compact bone portion 13 and an articular cartilage portion 15. Alternatively, if the bone plug 6 is taken from another individual, i.e., is an allograft, the supply of bone may be extremely small, which may effectively prevent individuals from receiving the necessary mosaicplasty. Bone plugs 6 are inserted through each of the cartilage layer 9 and compact bone layer 8 and into the cancellous bone 7.
Additionally, the bone plugs used in conjunction with mosaicplasty generally have very small articulating surfaces and, as a result, the number of bone plugs necessary to effectively repair and/or replace a focal defect may be substantial. These deficiencies are compounded when the legions cooperate to form kissing legions that require the performance of mosaicplasty techniques on both sides of the articulating joint.